Briquetted charge and process for producing phosphorus and potash therefrom



Patented Feb. 5, 1929.

} UNITED STATES WILLIAM H. WAGGAMAN AND HENRY W. EASTERWOOD, OI CHICAGOHEIWTS, ILLI- PATENT OFFICE.

N 018, ASSIGNOBS TO VICTOR CHEMICAL WORKS, OF OHIGAGO,,ILLINOIS, ACORPORA- TION or rumors.

BRIQUETTED CHARGE AND PROCESS FOR PRODUCING PHOSPHORUS POTASH THEREFROM.

'No Drawing.

This invention relates to a new and improved type of briquetted chargeand to processes of usin said charge for the production of phos ioricacid and potash in 5 various types of electric and fuel fired furnaces.It relates particularly to the use of briquetted mixtures of naturalphosphates; potash bearing silicates with or without additions of freesilica, and a solid reducing agent such as coal, coke, charcoal or thelike, in the roduction of phosphoric acid and potash by thevolatilization or pyrolytic process. It has for its object theaccomplishment of this purpose more expeditiously -and economically thanhas heretofore been possible.

This naces o the electrlc are or resistance type or fuel fired furnaces,of the blast furnace open hearth or reverberatory type, or in kilns ofthe shaft or rotary type ordinarily employed in the production of limeand cement.

In order that the invention may be clearly understood and distinguishedfrom the prior art, it may be said that it is a well known fact thatphosphoric acid and potash can both be volatilized as a whole or in partfrom properly proportioned intimate mixtures of natural phosphates, apotash bearing silicate, and a SOI'IdHfGdHCiIIg agent such as coal.or'coke, by heating said, mixtures to temperatures ranging from 1200 to1600 degrees C. The phosphoric acid and potash '35 thus volatilized canbe subsequently recovered either by absorption in water, "in a solutionof phosphoric acid, or by means of the Cottrell electrical precipitator,in a manner well known in the art.

The reactions which take place under these conditions may be representedby the following equations:

It has not yet been proposed however, to employ the mixtures abovedescribed in briquetted form. Neither has it been suggested" process maybe carried out in furheating source we have found that the inpresent inamounts more nearly equal to Application filed January 18, 1924. SerialNo. 687,124.

'to employ mixtures of natural phosphates,

potash silicate, and. coke or other solid reducing agents in types offurnaces other than the electric arc furnace. We have found that the useof a charge containing the above mentioned ingredients finely ground,thoroughly mixed, and moulded or pressed into briquettes, with orwithout the addition of a binding material, has distinct advantagesover' the use of a loose incoherent charge of the same or similarcomposition.

These advantages are: first, the Very close contact which can thus beobtained between the various ingredients in the charge, which permits ofa more prompt and rapid reac tion; and second, the ease with whichreducing conditions may be maintained where the carbonaceous material iswithin the body of the briquette and thus protected from externaloxidizing influences.

It is now generall agreed that ,in order to bring about comp etc ornearly complete elimination of phosphoric acid from mixtures of naturalhosphate, silica and carbonaceous materials, reducing conditions must bemaintained throughout the operation. In furnaces where fuel is used as acorporation of coal, coke or other carbonaceous material in the body ofthe briquette is the most efiicient and economical method of maintainingsaid reducing conditions.

We do not'wish to confine our process, 55 however, to the use of abriquetted charge of anyone definite composition, but we propose to sovary the proportions of the several'ingredients that we can obtain anyratio of acid to basic constituents, which may best be adapted to theprocess andto the type of furnace in which the heating of the charge isconducted. As an example, if we wish to obtain a fluid slag which can bereadily tapped from furnaces of the electric arc and blast furnacetypes, we so proportion the quantities of natural phosphate and potashsilicate that the lime, silicaand alumina are those in ordinary blastfurnace It is recognized that the raw materials which we propose to usein the briquetted charge contain various impurities such as compounds ofiron, manganese, magnesium,

titanium, sodium, etc., such impurities do not, however, affect ourbriquetted charge or our method of using such charge.

We claim:

1. The process for the production of phosphoric acid and potash by thevolatilization or pyrolytic method, consisting in heating in a chamberto a smelting temperature of from 1200 degrees to 1600 degrees C., anintimate briquetted mixture of a finely ground natural phosphate, apotash bearing silicate and a carbonaceous material until substantiallyall of the potash, phosphorus and phosphoric acid are driven off, andcollecting these volatile products.

2. The process for the production of phosphoric acid and potash by thevolatilization or pyrolytic method, consisting in heating in a chamberto a smelting temperature of from 1400 degrees to 1600 degrees 0., anintimate briquetted mixture of a finely ground natural phosphate, apotash bearing silicate, free silica, a carbonaceous material and abinder until substantially all of the potash, phosphorus and phosphoricacid are driven 0E, and collecting these volatile products.

3. The process for the production of phosphoric acid and potash by thevolatilization or pyrolytic method, consisting in heating in a verticalshaft furnace of the blast furnace type to a smelting temperature offrom 1400 degrees to 1600 degrees C. an intimate briquetted mixture of afinely ground natural phosphate, a potash bearing silicate, andcarbonaceous material until substantially all of the phosphoric acid,phosphorus and potash are driven off, and'collecting these volatileproducts.

4. The process for the production of phosphoric acid and potash by thevolatilization or pyrolytic method, consisting in heating in a verticalshaft furnace of the blast furnace type to a smelting temperature offrom 1400 degrees to 1600 degrees C. an intimate briquetted mixture of afinely ground natural phosphate, a potash bearing silicate, free silica,carbonaceous material and a binder, until substantially all of thephosphoric acid, phosphorus and potash are driven ofi' and collectingthese volatile products.

Signed at Chicago Heights, Cook 00., Ill.,

this 15th day of January, 1924.

WILLIAM H. WAGGAMAN. HENRY W.,EAS1ERWOOD.

